Toxicant carrier and pesticidal compositions containing same



United. States... Patent Q Y.

TOXICANT CARRIER AN 1)" PESTICIDAIT COMPO= SI'TIONS CONTAINING SAME,

erals-8z Chemicals Philipp Corporation, a corporation of Maryland" NoDrawing. Filed Nov. 4; 1957, Ser..No..694,1-18 8Claims. (Cl. 16,7--42}This invention relates to a novel, particulate composi; tion adapted tofunctionas a, carrier for a thiophosphate type toxicant and? topesticidalicompositions: including the.

same;

Thiophosphate-type toxicants' have the general structural formula:

R- O: S,

One of the most important members: of'this class of dimethyldithiophosphate; in which R is CH and R-f is sfieneo Q em, onto 0 00,11,

face of a chemically inert particulatemineral carrier and is readilyreleased thereby when-the composition is applied to crops. Frequentlythese initial compositions are further diluted or let-down with;low-sorptive particulate materials such as gypsum, talc and kaolinite ormixtures thereof. The desiderata' of anideal" mineral carrier are; lowcost, good flow properties, low bulk density, high 'sorptivity for thetoxicant and negligible effect on the potency of the active ingredient'impregnated thereon over prolonged storage of the composition. It hasbeen found that some highly sorptive clays such as attapulgite (Plygorskite), certain montmorillonite clays, mixtures of these clays, ormixtures of these clays with other clay minerals, such as kaoliniticclays, and kaolinite have a strong tendency to catalyze thedecomposition of a 'thiophosphate-type toxicant sorbed on the claysurface whereby the resultant insecticidal compositions have OIIIY ashort shelf life; after a few months of storage such compositions haveinadequate insecticidal potency.

It is aprimary object of the invention to teach -a novel method todeactivate the surface iof a sorptive clay so that a thiophospha'te-typetoxicant impregnated thereon has high stability :and ;aprolongedistorage life.

Another object of the invention is the preparation :of stableparticulate pesticidal compositions includinga .thio:phosphate-typetoxicant... a

Otherobjects will -be apparent; from a a reading of the followingdescriptionof the invention,

In brief; my inventioncontemplates the additionofa novel'- additive to asorptive clay to inhibit thltendency of *that'clay to-caitalyze-thedecomposition of "athiophos phate-typetoxicant-impregnatedthereon;

More specifically,- according tofthe teachings o f=the invention, asorptive clay in powdered or graham; state is treated withat; leastonenon-fugitive unsaturated or;

organicacid is preferably onethat is in the liquid state at about 20(3., although an acid liquifiable below the temperature. at whichdecomposition of the toxicant takes place, about 151C. in the case of'Malathioii, may be used.- The acid should preferably be in fluidstate'at the time of-distribution on the carrier so that admantributionof relatively small quantities of the additiveis feasible withoutrecourse to theuseof solventsI However, unsaturated acids that are inthe solid or semi-solid state between about 20 C and the decompositioiitemperature of the-toxicant or higher may be used, their distribution onthe earrier being "facilitated by'the employmentjof s.olvents. A furtherimportant'requiremeiit of the acid ist-hatithave a'low vapor pressure atroom temperature? an acid or acid mixture boiling with or withoutdecompos tion at above about 8,0, C. at 760; mm. is satisfactory. Ingeneral unsaturated acids having from about 6 to 22 carbon atoms aresuitable for the purpose. The acid or acid mixture may be added to thecarrier piior to or simultaneously with the impregnation, with thethiophosphate-type toxicant.

Although I do. not wish to be bound by the hypothesis herein setforth,it is believed that the surface catalyzed decomposition of athiophosphate-type toxicant is caused by the tendency of the carriersurface to promote boththe oxidation of. the double-bonded sulfur on thetoxicant molecule and the hydrolysis of the P-S -C linkagej the lattermechanism of decomposition being particularly favored by the presence of"water and calcium 'and/or metallic ions resident on the heterogeneousclay surface. Hence a tri-fold approach is herein made to counteract thetendency of the carrier surface to catalyze the decomposition pf thetoxicant sorbed thereon: (1) a material capable of being oxidizedpreferentially to the toxicant is added to the carrier to inhibitoxidative deterioration of said toxicant; (2) said material, being of anacidic character, tends to interact with available metallic ions,sequestering them in effect and decreasing the propensity of themetallic ions to catalyze hydrolysis of the P-S C linkage; and (3) sincethe organic acid tends to react with the available metallic ions in situsaid material acts as a barrier between the clay surface and sorbedmaterial to prevent the deleterious action resulting from direct contactof the toxicant molecule with potentially destructive sites on the claysurface.

The unsaturated acids are preferably chosen from fatty acids having atleast six carbon atoms and resin acids or admixtures thereof. Fattyacids are preferred to those olefinically unsaturated acids in which thedouble bond ispositioned so as to exert an appreciable influence on the.carboxy group. However, unsaturated fatty acids of the alpha-beta" orbeta-gamma types (preferably having at Patentedr'Novt 279',

3 4 least six carbon atoms) may be used when they do not u AND OTHERPOLYETHENOID FATTY ACIDS esterify the toxicants. Cmthmed The presence ofsaturated acids, hydrocarbons of acid or neutral character, oxygenatedorganic compounds of q acid or neutral character in the unsaturated acidor acids 5 Common Name Synonym $2 is not deleterious provided thematerial is not capable of oxidizing or reacting with (i.e., such astransesterification) 9, 11, woctadecamenoic 27351 th t i m cis-Q,cis-12,cls-l5 Octadecatrienoic- 273.51 A preferred additive from thestandpoint of economy ig 25 253 3 trans-15 octadec 273'51 is tall Oil,either unrefined, refined or highly refined, tall Pseudoeleostearictrails-10, grams-l2, trans-14 Octadec- 273.51 oil being essentially amixture of unsaturated fatty acids, q-Palillafic 9,1121%-Octadecatetraenoic 367. 34 e'l oleic and i i aside resin e The sense;2; 1, iaaaesaeseie:; a composition of the resin aclds 1n tall oil isessentially the same as that of the acid fractions of wood and gumrosins, that is, two doub!e-bond abietic-type acids, about 15 Thepneaturateq fatty made my be e rgp d as the 59%; ih acids (ahietie andpimarietype) about pure ac1ds or as mixtures, usually n assoc ation withfatty 15%; tetrahydro acids (includes pimaric-type acids) aboutacldshdenved h hydrolysls of 0115 of vegetahle 18%; dihydroabietic acid,about 3%; oxidized acids, about ahlma} 8 f example q h h 5% Resin acidsare l ifi d into two groups the grade oleic ac1d, so-called red oil smade from lnedible abietic type and the pimaric type, both beingcharacterized 0 tahPW grease and usually cohtams P to ahouh 7" by thepresence of two chemically reactive centers, the 01610 acid and thebalhhce aboht'eqhal P P hholelc d l bonds and the meneharboxyl group andhaving and the saturated acids, palm-inc and steanc. Other theoreticaliodine numbers f about 75 The double technical grades of oleic acid areavailable, these materlals bonds f the two deuhlehend ahietimype acidsare Com being characterized by the elimination of poly unsaturatedjugated in the pimaric type, hence the pimaric acid type acldsis moresusceptible to oxidation. The melting points of The Presence of anahhoxldaht m the held In amount of the pure resin acids or isomericmixtures is relatively from about to aboh? basefl oh the Welght of h hih that is, between about 150 and C" hence to unsaturated acid, isdesirable particularly where the ac1d be useful for the purposes of theinvention they must be or a shbstahhal Pomoh of h a Poly applied to thecarrier in a solvent or be used in conjunch acld acld hhxmre 15 Veg?"tion with fatty acids such as, for example, in a tall oil, table ohglhSufhcleht haturauy'occumhg phehhhc'type crude or fi d ta" oi].antioxidant, an inhibitol, such as sterol, tocopherol, etc., It will beunderstood, however, that the unsaturated is presellt so that a t e needhe h h acid or mixture of acids useful in the practice of the invenever,ahlmal fehty aclds, Parhculafly those hh 1h Poly tion is not restrictedto tall oil or to specific unsaturated ethehold cohshtuehts, arebenefited by addlhoh thereto fatty acids therein or the resin acid tothose specific ones of from about to Pwffimhly h P to in :tall oil.Other suitable unsaturated fatty acids and 0 of an ahhofhdaht whlch mayh j lhhlbltol' If properties th f are tabulated be1owgesgeddcotilnmercially availgbleddalzltioxidants sutelh :as

1n ere p eno s, etc., may e a e to increase e 1n- MONOETHENOID FATTYACIDS 40'hibitor level. These would be limited to compounds Theoretwhich have no deleterious effect on the phosphate-type Common NameSynonyms Iodine I tOXlcants- Value A suitable fatty acid mixture derivedfrom animal fat has a titer of 32.2 to 40 C., an iodine value (Wijs) ofggfigig" ggfigggg 53-5; 65-85, a free oleic acid content of 90-96%, andan acid lo-undqcyli'i lil-Undecenoice l t) 128111 value (mg. KOH) of179-191. Useful fatty acid mixtures efiggggg ghfg' gzgi ifg are derivedfrom cottonseed oil, soya oil, corn oil, palm gigg-ggtraleeglggn 1531;;gil, and many other oils. A iarticularly usedful liqillid j: atty acidhas a maximum titer 0 C., an io ine va ue fiiiiis h iiiiiifiaia j I:3323; (Wijs) of from 135-145, an acid value of 195-201; the gi'gggfgggff gif -g- 28-2; acid mixture analyzes about 40% oleic acid, abouttrans-n-octade euui' I s91 87 linoleic acid, and about 2% linolenicacid. A suitable g fijgPfiff ggfa Z1 83 fatty acid mixture derived fromsoya oil has a titer -of' 1823 C., iodine value of 120-125 (Wijs), acidvalue of 131., AND OTHER POLYETHENOID FATTY ACIDS 55 193-201, andanalyzes about 38% oleic acid, 43% linoleic acid, 2% linolenic acid andabout 9% saturated Theoret acids- Common Name y o y od n A typicalcommercially available oleic acid has a titer Value 1 about 5 0., aniodine value of -93 (Wijs), a saponification value of 195-203, and atypical composition iiihc 21:53:;gis'gzliewdem, mm 3583 of 79% oleicacid, 10% linoleic acid, 1% linolenic acid, assassin.-- tatiest-1zisaass a1- a 4% i acid, 5% palmific we and about 1%a-Elcostearic. cis-ilici s-n, trans-l3 Octadecafr iei; 273: 51 steam:acld: fl-Eleostearlc.-- midi-$961811,cis-iaoctadccamcn- 273.51 65 somesultable tall 011 composmons and Physical data 01c (7). are tabulatedbelow:

Whole 'Iall 011 'lall Oil Tall on Tall on Tall Oil Pitch Crude Low FattyResin Acid Acid 158-168 55-75 160-168 188-193 192-195 .lpglngdodifiedW1js) 190-210 -135 l70180 -165 -130 Fatty Acids. percent- 41-51 355044-54 70-66 96-98 Rosin Acids. percent.-. 37-42 24-32 40-50 28-321.5-2.5 Sterols, Higher Alcohols, etc.,

ES It is very important that the components of the deactivat be verythoroughly-' admixed with the carrier so that 'o' destrfictive siteson'fthecarrier' surface are avail able promotethe"deterioration 0f thetoxicant; Par

ticularly when very small quantities I of deiactiva'tor are used itmay-be desirable to add a solvent for the deactivator additive's toens'tire their' thoroiigh' distribution on i the lay surrace.--

The practice's tanght hereiif repaaiunm} beii at" low bulk density,superior flow characteristics low price position or the deactivatedcarrier; such techniques being' wellk own' to thosesk ille'd intheartl Asolvent may b added to'thecomponentsj of th'ede'activator to ensure theadequate distribution of" the dea'ctivator on thecarrier. I

The Malathion or otherthiophosphate-type' toxicant' maybe"impregnated'on' the carrier by milling, spraying, or solvent sprayingtechniques. Alternatively, the Malathion may be" added to the'carriertogether with the deactivator and be milledtogether.

The following examples and accompanying description are given "onlyfofthe purpose of better illustrating-the invention and'are' not to beconstrued as limiting. the scope thereof. I

Samples of at-tapulgite clay deactivated by the practice of the instantinventionwere impregnate'd'with about 5' percentby'we'igh't'ofatechnical gradeofMalathion, and

' mxicahr the" chemicalstabilityof the sorbed toxicant of each-- samplewas tested. H

The clay used was Attaclay, a finely powdered grade of fullers earthmade and sold by Mineralsi and Chemicals Corporation of America andhaving the followingspecifications:

Typical chemical composition (volatile-free basis) SiO perc" nt 6710 A10 do. 12.5 MgO do 11.0 Fe O do 4.0-- CaO do 2.5 Others d0 3.0 Averageparticle size (microns) 18 Oil absorption (ASTM D28131). 99 Freemoisture content (as produced) wt.

percent determined at 220 F. until constant weight is achieved. 0.2 pH(of water slurry) 7.0-8.0 Bulk-density- (lbs./cu. ft.)' 27-31Thesam'ples were formulated by' dripping: the Malathi-' onand-fiuid-deactivator' solution on the clay while mixing inaHobart mixerand then blending in the mixer for nevertheless display goodstability-characteristics -at-room-' temperature. It has been observedthat the results of such acceleratedtsts conductod to determine thestabilityof -toxicants sorbed-"on'a mineral' carrier, such as Attaclay,correspond to the stability data'foi' like'composi tions during storagefor much longer periods of time at anadditional'ZO minutes.-- Eachsample was then passed twice througha hammer mill and post blended on'a.

w 30 seconds.

the stability of thetoxicant under the. test conditions,

the'r'esidu'al Malathion concentration was ascertained "by a method"tobefdeserib'ed and was recorded as J the percentage of Malathion:chemically decomposed duringthestora'geperiodf It has been found thatMalathio impregnated ona" s'amp'le'ofuntreatedi Attaclay; at the 5%level, has a decomposition percentage of about vertedlto thecupriccomplxwhich issoluble in carbon.

tetrachloride with the formation of an intense yellow color. The colorintensity is"proportional to the concentration of To'prepar'e thestandard curve for Malathion dissolveap'prc'ixirhately 0.25 g. (weighedto 0.1 mg.) of pure Malathion'in 2j B ethanol contained in' a 250 ml.volumetric fiaskl Dilute to the mark:with 2-B ethanol. Mix

well; transfer a 25 ml. aliquot to a second 250 ml. volu-- metric flask,and dilute to the mark with 2-B ethanol. One ml. of this solution isequivalent to 0.1 mg. of Malathion. Carry 0, 2.5, 5, 10, 15, 20 and 25ml. aliquots of the standard solution through the following procedure.

Transfer each aliquot'to'a 250 ml. separatory funnel containingsuificient 2-B ethanol to make a total volume of exactly 25 ml. ofethanol. Add 1 ml. of 1% CS in 90 m1. ofcarbon tetrachloride;- Mix wellby swirling.

gently. Add mlrof 2% MaCl' solution (cooled to 15 (fl), containing 1 ml.of 0.1 N NaOH and shake vigorously for exactly 1 minute. Allow thelayers to separate and draw off the carbon tetrachloride layer into aclean, dry 250 ml. separatory funnel. Wash the aqueous layer once with10 ml. of carbon tetrachloride by shaking for 15 seconds, allow thephases to separate and add the carbon tetrachloride layer to themaincarbon tetrachloride solution, making certain that no water. istransferred to the separatory funnel containing the carbon tetrachloridelayers. Discard the alkaline salt solution.

Add 25 mlfof 2-B ethanoltothe' carbon'tetrachloride extract and swirl tomix. Add l-ml. of 6 N NaOH and shake exactly 1 minute. Immediately add75 ml. of 2% NaCl solution (cooled to 15 C.) and shake for exactly 1minute. Allow the phases -to separate and discard the carbontetrachloride layer. Wash the aqueous solution with 25 ml. of carbontetrachloride by shaking for Discard the carbon tetrachloride layer.

Add 25 ml. of carbon tetrachloride and 1 ml. of 7 N HCl to the aqueouslayer and shake for 30 seconds; Al-' To the aqueousphaseremainingintheseparatory fuii-q nel' addfrom" a pipette 5 0 ml. of carbontetrachlorideTand then 2 ml. of copper sulfate solution. Immediatelytemperatu e. nts end of the storage period wvhi'ch the'Malathiodcoinpositions' were held I in for 1 minute and allow thephases to separate. Immediately measure the absorbance of the yellowsolution of 420 mu using carbon tetrachloride as the reference.

Prepare the standard curve by plotting the absorbance 8 I claim: 1. Acarrier for a thiophosphate-type toxicant in solid particulate formcomprising a sorptive naturally occurring siliceous mineral havingdistributed on the surface thereof each of the above aliquot vs. the mg.of Malathion. 5 of at least one unsaturated organic acid in an amount ofTo analyze the powders containing Malathion, a samfrom about 5% to aboutby weight based on the plc is weighed to the nearest milligram into avolumetric weight of said siliceous mlneral, said unsaturated orgamcflask and diluted to the mark with 2-B ethanol. Serial acid beingselected from the group consisting of unsatudilutions are made so thatthe final amount of Malathion rated fatty acids and resin acids havingfrom about 6 to analyzed is 1.0 to 1.5 mg. 10 22 carbon atoms and havingan Iodine Number of at Samples of pesticidal compositions containingabout 5 least about 70 percent by weight of Malathion were chosen forobserva- 2. The carrier of clalm 1 1n which the siliceous mineral tionsince absolute decomposition, based on the original is attapulgiteweight of Malathion present would show up better than 3. The carrierofclaim 1 m which the slhceous mmeral if observations were made on ahigher concentration powis montmorillonite. der, such as 25 percentMalathion. On an absolute basis, 4. A pest1c1dal composition in sohdparticulate form decomposition should be substantially identical for 5comprising a sorptlve naturally occurring sillceous minpercent and 25percent Malathion formulations. It is to oral having distributed on thesurface thereof a th1opho 9- be clearly understood that a 5 percentMalathion concenphate-type toxicant and at least one unsaturated orgamctration was chosen merely to magnify decomposition efacid selected fromthe group consisting of unsaturated fects and not to restrict the scopeof the invention to such fatty aclds and ln ids aving from about 6 to 22a composition. An inexpensive, inactive, relatively noncarbon atoms andhaving an Iodine Number of at least sorptive carrier may be added toformulations to produce about sald unsaturated organic acld belns p t Infield strength compositions. an amount of from about 5% to about 10% byweight 25 based on the weight of said siliceous mineral. EXAMPLE 1 5.The pesticidal composition of claim 4 in which the The ability ofseveral grades of tall oil to reduce the siliceous mineral isattapulgite. tendency of Attaclay to decompose a thiophosphate-type 6.The pesticidal composition of claim 4 in which the toxicant, Malathion,is demonstrated. Attaclay Was simulsiliceous mineral is montmorillonite.taneously impregnated with 5.2% by weight of atechnical 7. A pesticidalcomposition in solid particulate form grade of Malathion and severalcommercially available comprising attapulgite having distributed on thesurface liquid grades of tail oils, in varying quantities. In thethereof Malathion and at least one unsaturated organic case of tall oilsample B, a highly viscous composition, acid selected from the groupconsisting of unsaturated the Malathion was admixed with the oil and theresultant fatty acids and resin acids having from about 6 to 22 massimpregnated on thecarrier. All samples were held carbon atoms and havingan Iodine Number of at least in sealed jars at C. for one month. Thecomposition about 70, said organic acid being present in an amount andphysical properties of the tall oil samples are as folof from about 5%to about 10% by weight based on the lows: weight of said attapulgite.

A B o D E F General Type, (Ll High Fatty High Whole Whole Distilled AcidRosin Whole Tal101l 'Iall on Tall 011 TallOil Acid Tall 011 Tall On AcidNo 180-185 -168 188-193 192-195 -170 160-168 Saponificatiou No 181-186163-173 190-195 195-198 168-178 -175 Rosin Acids, percent.-. 30-33 37-4228-32 0.8-1.2 q.s. 40-50 Fatty Acids, percent 61-66 47-57 70-66 96-980-3 44-54 Linoleic 48% Oleie 50% Sat. 2% Unsaponifiables (Sterois,Higher Alcohols. etc.) 4-6 6-9 1. 5-22 1. 5-25 6-9 Iodine No. (Wiis)-180 -210 155-165 127-133 170-180 Moisture, percent 0.1 Max. 0.1.0 NoneNone 0.2-1 Viscosity, SUS 210 F 12-62 85-110 54 93 90-120 Modified Wijsusing 300:!=l0% excess iodine at 25i0.5 C. for 30 minutes.

Exceptas noted, methods are according to ASTM D803-44T.

The results of impregnating the Attaclay with portions of the above oilsare tabulated below:

It will be understood that the invention is susceptible to numerousembodiments without departing from the spiritvand scope thereof and,therefore, only such limitations should be imposed as are indicated inthe appended claims;

8. A pesticidal composition in solid particulate form comprisingattapulgite having distributed on the surface thereof parathion and atleast one unsaturated organic acid selected from the group consisting ofunsaturated fatty acids and resin acids having from about 6 to 22 carbonatoms and having an Iodine Number of at least about 70, said organicacid being present in an amount of from about 5% to about 10% by weightbased on the Weight of said attapulgite.

References Cited in the file of this patent UNITED STATES PATENTS DolmanJuly 6, 1943 Lindstaedt Dec. 6, 1932 OTHER REFERENCES Yost: MalathionFormulations, Agr. Chem., October 1955. Pp- 105, 107, 44-44. a

1. A CARRIER FOR A THIOPHOSPHATE-TYPE TOXICANT IN SOLID PARTICULATE FORMCOMPRISING A SORPTIVE NATURALLY OCCURING SILICONES MINERAL HAVINGDISTRIBUTED ON THE SURFACE THEREOF AT LEAST UNSATURATED ORGANIC ACID INAN AMOUNT OF FROM ABOUT 5% TO ABOUT 10% BY WEIGHT BASED ON THE WEIGHT OFSAID SILICEOUS MINERAL, SAID UNSATURATED ORGANIC ACID BEING SELECTEDFROM THE GROUP CONSISTING OF UNSATURATED FATTY ACIDS AND RESIN ACIDSHAVING FROM ABOUT 6 TO 22 CARBON ATOMS AND HAVING AN IODINE NUMBER OF ATLEAST ABOUT 70.